Portable bending brake



Nov. 28, 19

J. JENSEN 2,181,566

PORTABLE BENDING BRAKE 2 Sheets-Sheet l Filed June 29, 1936 Nov. 28, l1939. 1 JENSEN 2,181,566

" PORTABLE BENDING BRAKE Filed June 29, 1936 2 Sheets-Sheet 2 Patented Nov. 28, 1939 PATENT OFFICE PORTABLE BENDING BRAKE John Jensen, Rockford, Ill., assigner to yWhitney Metal Tool Company, Rockford, Ill., a corporation of Illinois Application June 29, 1936, serial No. 87,919

3 Claims.

The invention relates to a brake for bending sheet metal and more particularly to portable brakes of this type.l

Most bending brakes for sheet metal heretofore available were very heavy and unwieldy. It has been the general practice to locate them in shops or facto-ries where sheet metal structures were preformed either as a whole or in sections and then transported to the point of installation. This practice has proved to be particularly `unsatisfactory and the source of many vexatious delays in the installation of conduits in houses and oice buildings for air conditioning systems, for example, since the sheet metal work required is quite extensive and must be specially formed to fit the particular dimensions and irregularities of the structure in which it is placed.

The principal vobject of the present invention is to provide a bending brake that is simple and light in construction withoutsacrice in ruggedness and rigidity ofparts, its parts being arranged in a novel manner such that the complete machine can be readily transported to and operated at various places where the sheet metal articles formed thereon are to be used.

Another object of the invention is to provide a machine of the character described which is readily and accurately adjustable to bend metal sheets of different thickness, and which may be readily adapted to perform a variety of different types of bending operations, thus obviating the necessity of transporting several machines to the place of installation for performing the various bending operations required.

Further objects and advantages ofthe invention, will become apparent as the following description proceeds and the features of novelty, which characterize the invention, are pointed out with particularity in the claimslannexed to and forming a part of this speciiication.

For a better understanding of the invention reference may be had .to the accompanying draw-` ings, in which: v

Figure l is a perspective View of a bending brake embodying the present invention.

Fig. 2 is an end view of the machine shown in Fig. l with certain parts broken away.`

Fig. 3 is a transverse section of the bending brake shown in Fig. 1 illustrating particularly the detachable lingers secured to the platen for use in bending box forms and the like, and

Fig. 4 isla perspective View of a portion of the machine shown in Figs. l toA 3, further illustrating the detachable fingers included in Fig. 3.

As shown in the drawings, they invention herein disclosed is embodied in a portable bending brake particularly adapted for performing various bending operations on sheets of metal,

The bending brake illustrated includes as its principal working elements a movable pair of jaws formed by the platen I0 and a bed Il adapted to clamp a sheet of metal therebetween and an apron I2 adapted to bend the clamped sheet of metal about the forward edge of the platen when swung toward the same. y

The bed is as light in constructionv as is possible in view of the heavy compressive'forces which it is required to withstand. In the machine illustrated, the bed is formed by a bar or wear plate I3 extending along the forwardedge of a steel beam I4 having a T-shaped cross section. The iiat upper portion of the beam forms an ample support for certain parts of the brake such as the wear plate I3 while the vertical portion thereof forms a strengthening web adding rigidity to the structure. The bar I3 is preferably welded as indicated at I5 (Fig. 3), or otherwise rigidly secured. to the beam I4 by the fusion of metal, thus eliminating any bolts or the like in the connection. The beam lll thus forms a rigid lightweight supportfor the bar I3. It will be understood that the bar or wear plate I3 may be readily replaced by a duplicate member if it becomes scarred or otherwise injured after continued use.

The vbeam I4 is supported on' a frame work which is of minimum height and weight in order that the bending "brake may be supported on a work bench or in any similar place which happens to be convenient at the building in Whichthe sheet metal work is being installed. The frame work illustrated includes a pairv of rectangular end members designated by the numeral I6. Each of the end members I6 includes a generally U-shaped portion I1 made of a continuous piece of angle iron bent to the desired shape.. An oirset I8 is formed in the forward legs of each of the members I'I so as to accommodate the apron I2 as well as the linkage mechanism for operating the platen Ill. At the same time, the elongatedy bottom faces of the members Il form a base located closely adjacent the bed II and of maximum length from front to rear thus imparting a high degree of stability to the structure.

The upper ends of the legs of the members I1y are joined by transversely extending angle irons or rails I9. The end portions of the beam I4 are rigidly secured tothe adjacent upper front corner portions of the end frames I6 by -bolts Ill@` andv I4?, while the rear upper corner portions of the end frames are secured together by a tie-bar 20.

The bending brake is illustrated in Fig. l as supported on a light frame work consisting or rectangular end members I6a made of angle iron and having theirI lower portions secured together by a tie-rod lb. The lower sides of the end member I1 of the brake are detachably secured to the horizontal upper rails of the frames Iiia by bolts Ha. The brake may be readily removed from the frame work illustrated by detachment of the bolts I'l.

The platen I0 is preferably of fabricated construction in order to minimize its weight. In the machine illustrated, the platen is of generally box-like construction and includes an angularly disposed face plate 2i reinforced by a supporting structure which is triangularly shaped in cross section, being formed by plates 22 and 23 welded to each other and to the edge portions of the face plate 2l. The lower forward edge of the face plate 2'! carries a blade 24 constituting the bending edge proper of the platen. It will be noted that the blade 24 forms a continuous bending edge extending substantially throughout the longitudinal length of the platen il). The blade 24 thus cooperates with the bar I3 to clamp and support a sheet of metal therebetween.

The platen lli)V is movably supported and is operable by a simple form of linkage mechanism to move the same toward and away from the bed II in a substantially vertical direction. The supporting arrangement for the platen it includes a pair of levers 25 welded to the opposite ends thereof as indicated at 2E. As shown in Figs. l and 2, the rear ends of the levers 25 are connected to brackets 27 by pivot pins 2d when the bending brake is conditioned for forming continuous bends in plane sheets of metal. An arrangement hereinafter described is also provided for shifting the points of pivotal connection between the levers 25 and brackets 2'! when detachable bending fingers are secured to the platen I3 in order to effect box bending operations and the As shown in Fig. 2 the brackets 2 are adjustably secured to the rails or angle irons I3 by bolts 29 passing through suitable slots formed in the horizontal portions of the rails IS. Adjusting screws 3i) and 3I threaded in brackets 32 and 33, respectively, bear against the opposite ends of the bracket 21 and may be utilized to adjust the same to the exact position desired for bringing the forward edge of the blade 24 into alinement with the forward edge of the bar I3.

The platen EEJ is moved into and out of clamping engagement with a sheet of metal interposed between the bed and the platen by a linkage mechanism including independent manual operating levers 3H positioned at opposite ends of the bending brake. The lower U-shaped ends of the levers 34 are pivotally supported by a shaft 35 extending therebetween and journaled in suitable forwardly extending brackets 36 secured to the forwardlegs of the U-shaped frame member il. The forward ends of the levers 25 are connected to the operating levers 34 by links 3l. It will be noted that the upper ends of the links 3'! are pivotally connected to the levers 25, while the lower ends thereof are pivotally connected to the U- shaped lower end portions of the manual operating levers 3d at points eccentric wtih respect to the shaft 35. It will thus be seen that when 'the manual operating levers are rotatedfrom the position shown in Figs. 1 and 2 that the links 3l will be moved upwardly, consequently swinging the levers 25 in a clockwise direction about their pivots 23 and thus moving the platen I0 away from the bed II. The pivots 28 are preferably located above the plane of' the bed II and at a maximum distance laterally therefrom so that the horizontal component of the movement of the platen I0, during its swinging motion about the pivots, will be minimized. It Will be noted that the shaft 35 interconnects the operating mechanisms at the two ends of the brake so that kit may be operated at will from either end. Moreover the position of the shaft 35 in the offsets in the front frame work legs prevents its interference with the rest of the machine.

The apron I2, hingedly connected to the bed and operable to bend a sheet of metal secured between the bed and platen, consists in general of: a normally depending leaf iii supported with its upper rear edge as nearly as possible coincident with the upper front edge of the bar I3 on the bed II. Hinge straps Hr are bolted to the opposite ends of the leaf d. These hinge straps are provided with enlarged forked upper ends 43 journaled on pins Ml mounted in hinge brackets i5 bolted to the opposite ends of the beam I4. 43S are secured to the inner face of the leaf it adjacent the ends thereof and form handles for swinging the same upwardly into operative relation with a sheet of metal clamped between the platen and the bed. ri'he apron l2 and platen l@ are provided with reinforcing trusses E23 and We, respectively. From the foregoing it Awill be seen that the operating mechanism of the bending brake is sufciently compact that it is located entirely above the lower surfaces of the supports i'l and may consequently oe operated free of interference when placed on a work table or the like.

When the machine is arranged, as shown in Fig. l, it is adapted to form continuous bends in plane sheets of metal about the elongated edge of the blade 24 on the platen Id. In many instances, however, it is desirable to form discontinuous bends in a sheet of metal as, for example, when box forms are being made. Consequently, an arrangement has been provided by means of which the machine illustrated may be adapted for performing this latter type of bending operation. As a result, the utility of the machine is greatly enhanced as well as the practicability of its use at the site on which the sheet metal work is to be erected, since the necessity of providing separate machines for various types of bending operations would greatly'handicap the workmen in this latter type of operation. The arrangement for converting the machine to a box bending brake includes, in general, a plurality of bending lingers which may be detachably secured to the platen I0.

In the preferred arrangement illustrated in Figs. 3 and 4, for example, bending fingers 41 are detachably secured to the platen I il. The detachable securing arrangement includesva rearwardly disposed hooked portion iwhich ts over an undercut plate e9 detachably secured to the lower f'ace of the platen lil. After the rear portion 3 of the fingers :il has been hooked over the plate lig, the front portion of the fingers is secured to the blade 24 by an undercut plate 50 which is detachably secured to the fingers 27 by bolts 5I. As best shown in Fig. 3, when the fingers i7 are thus positioned on the platen Ill, the forward edge thereof is arranged substantially in alinement with the forward edge of the bar I3 on the rbed I l. To position the ngers in this Way GIl it is necessary, however, to shift the platen yIll" f E when the fingers 4l are secured in place on the platen lil.

or adjusting collars 54. The lengths of the links 3l may thus be conveniently Varied to accommodate the change-in position of the platen l0 by threading the members 52 and 53 into or out of the collars Eli. This adjustable construction of the links 3l is also advantageous in that the spac- 24 from lthebar I3 on the bed` ing of the blade ll may be conveniently varied by changing the length of the links 3l in order to accommodate sheets of metalof different thicknesses when the blade 2Q is being utilized without the fingers 41 to perform plane sheet bending operations. The pivotal supporting brackets 21 maybe adjusted along fthe rails I9 to bring the forward bending edges-of the ngers l `or blade 24, as the case may be, into registry with the forward edge of thev bar i3 after the desired changes have been made in the operating and supporting linkages of the platen l0. A sheet of metal 41a is shown in Fig.l 4 clamped between ngers'l'l and bedvl3 prior to bending the same in a boxform. The fingers accommodate the upturned edges of the sheet.l

From the foregoing it will be apparent that a bending brake has been provided which is .extremely light in weight without sacrifice in rigidity and ruggedness of construction. The improved form of frame workand mounting ar-l rangement for the parts of the bending brake contribute materially to this reduction in Weight' as does the fabricated construction of the platen and bed. This improved form of fabricated construction of the platen and bed effects a reduction v in weight by the elimination of gusset plates and similar bracing members, as well as a large number of bolts and the like. It should also be noted that the improved bending brake illustrated is constructed largely of standard structural steel parts or forms so that the cost of manufacture is likewise minimized. K

Although a particular embodiment of the invention has been shown and describedin detail for purposes of illustration there is no intention I to thereby limit the invention totheparticular n construction illustrated but on the other yhand the appended claims are intended to cover all modifications withinthe spirit and scope of the invention.

I claim as my invention:

l. A portable sheet metal bending brake comprising, in combination, a bed including a rigid horizontal beam, a supporting frame work for said bed including substantially U-shaped members formed from continuous lengths of metal at- In the particular machine illustrated, the links 3l include end members 52 and 53 having their adjacent ends threaded in 'turn buckles impart a high degree of stability to the brake,

the small height of the brake permitting ready portability thereof and alternative mounting on eithera suitable frame Work or bench, a platen pivotally mounted `on said frame Work, means including an operating mechanism located wholly above said bottom portions of said' U-shaped members for swinging ksaid platen toward and'l away from said bed to clamp-'a sheet of metal therebetween, and an apron hingedly mounted on said beam and swingable toward said platen to bend a sheet of'metal clamped between said bed and platen, the front legs of said U-shaped members being provided with inwardly extending' offset portionstherein adapted to laccommodate said apron when in its lowermost position. f

2. A portable sheet metal bending brake comprising, in combination, ra bed including a'rigid horizontal beam, a supporting frame work for said bed including substantially rectangular end members secured to the ends of said beam and adapted to support the same on a tableor the like, a platen pivotally mounted on said frame work, said end members being provided with elongated base portions extending from front to `rear thereof and'located closely adjacent -said beam, the front legs of saidrectangular end members being disposed rearwardly of the front ends of said base portions, a platen pivotally mounted above said bed for swinging movement toward and away from the same, loperating mechanisms located at each end .of said beam and operable at will from either end thereof for moving said platen toward and away from said bed, means including a shaft extending along vthe front of said front legs and supportedthereon for interconnecting said operating mechanisms in operative relation, and an apron hingedly mounted on said beam and swingable toward 'said platen to bend a sheet of metal clamped between said bed and platen.` y

3.- A bending brake comprising,in combination,

a frame work, ar bed carried by said frame work, brackets mounted for horizontal sliding movementv on said frame work, means for detachably securing said brackets in a selected position on said frame work, a vplaten having a forwardly-'dsposed continuous bending edge and rearwardly extending supporting arms, lingers adapted to be carried by said platen to provide a discontinuous 'box bending` edge located forwardly lofV said continuous bending edge, means for pivotally connecting said arms to said brackets at either of two selected points along said arms to bring one or the other of said bending edges approximately into alinement with the bed, the adjustment of said brackets serving to effect the exact alinement desired, and a bending apron hingedly supported on .said bed. f

`JOHN JENSEN. 

